Running wires through fuel tank safely?
 

Hello fellows, I've added 2 wires for my fuel level unit that I somehow need to run through the lid of the fuel level unit. Goes without saying that it needs to be a vapour and fluid proof connection.
I've been unable to find any press fit connectors like the ones Honda use. Or anything similar for that matter. I'm not excactly sure what to look for. Would you call it a bulkhead connector?

Do you guys have any suggestions on what to use???

I'm beggining to consider just drilling 2 holes in the lid, then slide some rubber sleeves over the wires, pull them through the lid and seal it up with a sealant...
Another idea was to use 2 small solid rubber cylinders, drill a hole through the center of them. Then drill a hole through the fuel unit lid. Place the 2 rubber cylinders on each side of the lid, then stick a small 3mm bolt through the hole with a washer and a nut on each end of the bolt. Then as you tighten the nuts the rubber expands and seals. The bolt then acts as the electrical connector. Only problem is the bolt and nut connection itself does not provide an air/watertight seal.

I added pics of the fuel level unit in question.


https://img178.imageshack.us/img178/...gp3177kopi.jpg

https://img26.imageshack.us/img26/2731/imgp3179kopi.jpg

https://img525.imageshack.us/img525/...gp3180kopi.jpg

Example of another honda fuel level unit:

https://img709.imageshack.us/img709/...gp3173kopi.jpg

Re: Running wires through fuel tank safely?
 

I was just in the same boat myself.

What I ended up doing was drilling a hole in the sending unit and running a stainless bolt through with a Stat-O-Seal crush washer (available from most places: pegasus, summit etc) on the top and bottom sides. I put the bolt head on the bottom side, and tightended it down on the top side with a nut. I used a ring terminal to attach the wire on the bottom side of the sending unit, and the same on the top. Works great. Completely gas tight.

Re: Running wires through fuel tank safely?
 

Subscribed!

It's incredibly difficult to find information on this subject.

Re: Running wires through fuel tank safely?
 

Im not sure if I'm getting that right? If the stainless bolt was in contact with the metal part of the crush washer, then the washer would be able to conduct electricity between the bolt and the lid of the sending unit, no?

Re: Running wires through fuel tank safely?
 

I was very concerned with that, and I noticed I left out a step when reading over my post...the key was to use the stat-o-seal crush washers (they have rubber edges that flare up when tightened down), and drill the hole in the sending unit top larger than the bolt. Around the bolt, and between the sending unit lid I used a thick rubber o-ring to keep it isolated from the actual lid surface. So far I haven't been able to test any continuity between the bolt and the sending unit lid. For extra peace of mind I'm going to go back and put a teflon washer between each lid surface.

At first I had carved some rubber "bushings" out of larger piece of rubber that looked like control arm bushing...you know, a mushroom looking chunk of rubber with a hole drilled in the middle. One mushroom "head" bushing would go above the sender and one mushroom "head" bushing would go below the sender. Then I would put a bolt through it. When I tightened the bolt, it would expand the mini control arm bushings and form a water tight/electrical isolation seal. I got one "bushing" carved and ran out of rubber. You know how the rubber freeze plugs work? Same idea.

I will say we may be over-analyzing it too much.....

I was at a very prominent tuning/fabrication shop the other day (wont mention any names) and I saw them working a fuel pump setup. You know how they solved this scenario?

Drill a hole, run the wires through it, and JB Weld the heck out of the top and bottom. Not very elegant, but I guess it works.

The problem with using a "sealant" like you suggested is that not many sealants are gasoline resistant. If you were going to try to do that I would just go with the JBWeld idea.

I would love to hear other ideas!

Re: Running wires through fuel tank safely?
 

Alright thanks. What you did is similar to/the same as my idea then. Except you're using the stat-o-seal to seal up the nut-bolt connection.

I've found this sealant from 3M that is gasoline resistant. So I'm probably going to try getting some of that:
http://www.auto112.dk/images/autoka/5000108531.jpg

And I'm not sure but it seems that polysulfide based sealants are gasoline resistant.

Re: Running wires through fuel tank safely?
 

http://www.reganrotaryracing.com/fddualfuelpumps.htm

using these

http://www.summitracing.com/parts/SUM-G1431/?rtype=10

Interesting idea. I wonder if the plastic on those bulkhead fittings is gasoline resistant?

They are probably way too large (physically) for your application, but cool idea IMO.

Re: Running wires through fuel tank safely?
 

I made a fuel injector cleaner with a Honda fuel pump, rail, and FPR, so I had this problem too. To get the wires in w/o using the stock civic tank cap, I ran an electrical bulkhead tube that was a threaded tube with two nuts on either end. I used a gas-safe sealant on the threads, fished the wires through, the sealed the inside of the tube with that sealant.

However, for a road-going setup, those $10 electrical fittings above look perfect.

Re: Running wires through fuel tank safely?
 

I have one of those around actually but as you thought they are way big to fit 2 of them on my fuel sensor. Even 1 would be critical lol.

Thanks I did look at those bulkhead tube thingies, but seems they are all rather large diameter.

Re: Running wires through fuel tank safely?
 

Re: Running wires through fuel tank safely?
 

^^ Nice. I think those would be a bit over the top in my case though.

Here's what I ended up doing. I drilled the holes in the lid as small as possible to make a very tight fit between the rubber grommets and the bolts. Hopefully that is enough to seal around the threads of the bolt.

Re: Running wires through fuel tank safely?
 

^ Looks good. Although I probably would have ditched the plastic insulator and crimp, and soldered and used shrink tubing just to be positive it doesn't come loose.

Re: Running wires through fuel tank safely?
 

Yea you're right. I'll probably do that the next time i pull it out of the tank.

But now I finally have a working fuel level indicator, yay :) Have been running with only the fuel reserve indicator for years lol.

Re: Running wires through fuel tank safely?
 

The bulkhead I got was from Home Depot (hardware store in USA). It was a brass or brass-colored for lamps or something, ~1/4" ID.

Re: Running wires through fuel tank safely?
 

Ever see how full blown does it on their hangers that come pre-wired?

Drill a hole, throw the wires though, and JB weld it up nicely/cleanly? Im not sure exactly what fullblown uses for sealant it sure looks like JB weld though :P

Re: Running wires through fuel tank safely?
 

We have had good success with these, http://www.altechcorp.com/PDFS/LTSR_Straight.pdf

Re: Running wires through fuel tank safely?
 

i know this is an old thread but i just found this!
http://www.racetronix.biz/itemdesc.asp?ic=BCWS-001&Tp=
hope it help someone like me searching for info.

Re: Running wires through fuel tank safely?
 

someone sticky this,great find!!!

Re: Running wires through fuel tank safely?
 

link dosent work

Re: Running wires through fuel tank safely?
 

works fine